4 - 1
SECTION 4
CIRCUIT DESCRIPTION
• 118–173.995 MHz
The RX signals are passed through two LPFs, ANT SW,
ATT and band SW, then applied to the RF AMP (Q400). The
amplified RX signals are passed through the tuned BPF,
and applied to another RF AMP (Q401). The amplified RX
signals are passed through tuned BPF, then applied to the
1st IF mixer (IC900) via the band SW.
• 174–259.995 MHz
The RX signals are passed through the LPF, HPF, ANT SW,
ATT, band SW, HPF and another band SW insequence,
then applied to the RF AMP (Q300) via the tuned BPF. The
amplified RX signals are passed through another tuned BPF,
then applied to another RF AMP (Q301). The amplified RX
signals are applied to the 1st mixer (IC900) via the band SW.
• 260–349.995 MHz and 470–599.995 MHz
The RX signals are passed through the LPF, HPFANT SW,
ATT, BAND SW and tuned BPF in sequence, then applied to
the RF AMP (Q500). The amplified RX signals are passed
through another 2pole tuned BPF, and applied to another
RF AMP (Q501). The amplified RX signals are then applied
to the 1st mixer (IC900) via the band SW.
• 350–469.995 MHz
The RX signals are passed through the LPF, HPF, ANT
SW, ATT, band SW and HPF in sequence, then applied to
the RF AMP (Q600). The amplified RX signals are passed
through the tuned BPF, and applied to the RF AMP (Q601).
The amplified RX signals are passed through the BPF, then
applied to the 1st mixer (IC900) via the band SW.
4-1 RECEIVER CIRCUITS
RF CIRCUITS (RF UNIT)
RX signals from the antenna are sorted by its frequency by
the filters and gone through RF circuits for each bands. And
this transceiver also has two RX lines for two independent
operating bands; A BAND and B BAND.
<A BAND>
• 76 MHz and below
The RX signals are passed through two LPFs, ANT SW,
ATT, band SW and LPF. The RX signals are sorted by its
frequency by band SWs.
• 0.495–29.995 MHz
The RX signals are passed through the band SW (D201)
and LPF, and applied to tuned RF AMP (Q200). The
amplified RX signals are applied to the 1st mixer (IC900) via
the band SW (D203).
• 30–75.995 MHz
The RX signals are passed through the band SW (D250)
and tuned BPF, and applied to the RF AMP (Q250). The
amplified RX signals are passed through tuned BPF, then
applied to the 1st IF mixer (IC900) via the band SW (D256).
• 76–117.995 MHz
The RX signals are passed through two LPFs, ANT SW, ATT,
band SW, LPF and another band SW in sequence, then applied
to the RF AMP (Q300) via the tuned BPF. The amplified RX
signals are passed through another tuned BPF, then applied to
another RF AMP (Q301). The amplified RX signals are applied
to the 1st mixer (IC900) via the band SW (D311).
• RF CIRCUITS
RF
AMP
ANT
SW
RF
AMP
RF
AMP
LPF
BAND
SW
BPF
ATT
BAND
SW
RF
SW
RF
AMP
BAND
SW
RF
SW
LPF
BAND
SW
BPF
BPF
RF
AMP
HP F
RF
SW
BPF
HP F
BPF
BAND
SW
ATT
RF
AMP
LPF
BAND
SW
RF
AMP
BPF
RF
AMP
BPF
LPF
BPF
RF
AMP
RF
SW
BAND
SW
ATT
LPF
BPF
BAND
SW
RF
AMP
BPF
BPF
BAND
SW
BPF
RF
AM P
ANT
SW
RF
AMP
BAND
SW
BAND
SW
BAND
SW
BAND
SW
BPF
BAND
SW
BAND
SW
BPF
BAND
SW
BPF
RF
AMP
RF
AMP
HP F
BPF
D9
Q1,2,150
D1,3,4,10,151,160
Q1,3,D6-8
D304,305
Q601
D604,605
D606
D400
D702
Q401
Q701
D402,403
D405
D200
D250
D254,255
D508
D253
D705
D603
D311
D655
Q400
Q700
Q450
D454
D201
Q500
D252
D600
D300
D650,651
Q300
Q651
D653,654
D302
D700
D401
D703,704
D404
D706
D451,452
D500
Q200
D503
D251
D256
Q600
D301
D306-309
D652
Q301
D303
D 701
D450
D453
D5
D501,502
D203
D504,507
Q250
Q501
D202
D601,602
To 1st mixer
(IC50)
for B BAND
To 1st mixer
(IC900)
for A BAND
D310
A:0.5−30MHz
A:30−76MHz
Tx:430.000−450.000MHz
Tx:144.000−148.000MHz
A:174−260MHz
A:76−118MHz
A:118−174MHz
B:118−174MHz
A:470−600MHz
A:260−350MHz
A:350−470MHz
A:350−470MHz
B:350−470MHz
A:600−1000MHz
HP F
L1-3
C1-6
L4,C7-9
L200,201
C201-204
L300,301
C301-305
L600,608
C600-602,630,631
L8,9
C18-20
L302,303
C306-310
L202,203
C205-9
L5-7
C10-14
